Originally a packet used in TCP/IP to establish a connection, it is now commonly used as an "Are you there?" request to another user on a talker. It is also used in the less common form "SYN SYN ENQ" - two SYNchronization bytes, then an ENQuiry. The latter form is pretty much the same as the former.

SYN is a youth radio station on air in Melbourne, Australia. Acheiving cult popularity levels, SYN 907 has won legions of young (and old) fans with its unique mix of indie, Asian pop, hip-hop, punk/metal, beats, youth content, amazing local bands, and The Naughty Rude Show.